Question 1

Urea is used as a source of nitrogen in fertilizer. The second step of the synthesis is heating the intermediate ammonium carbamate to produce urea shown in the equation below: NH₂CO₂$\rarr$NH₄ O)NH₂ + H₂O The reaction proceeds in 60% yield, on average, and the product is mixed with unreacted starting materials, which are readily separated from the product. They can then be recycled and undergo the process again. If one starts with 1 kg of ammonium carbamate, how many times will it have to be cycled through this reaction to give at least a 90% yield?

Accepted Answer

To achieve at least a 90% yield starting from 1 kg of ammonium carbamate with an average yield of 60% per cycle, the material needs to be cycled through the reaction three times. After the first cycle, 60% yield gives 0.6 kg of urea. Recycling the unreacted material (40% of 1 kg = 0.4 kg) through a second cycle yields an additional 0.24 kg (60% of 0.4 kg), totaling 0.84 kg. Recycling the remaining unreacted material (40% of 0.4 kg = 0.16 kg) through a third cycle yields an additional 0.096 kg (60% of 0.16 kg), totaling 0.936 kg, which is over 90% of the initial 1 kg.

Question 2

How many kg of ethylene oxide is needed to produce 1.05 x 10⁴ kg of ethylene glycol by the following reaction that proceeds in 95% yield?

Accepted Answer

The answer of How many kg of ethylene oxide is...

Question 3

A way of generating dry O₂ in the lab is to heat potassium chlorate. If you determined that 25 grams of O₂are needed, how much potassium chlorate do you need to start with if there is only a 60% yield?

Accepted Answer

The answer of A way of generating dry O₂ in...

Question 4

Hydrazine (N₂H₄) is made by the reaction of ammonia (NH₃) with hypochlorite (OCl^-). Given the following equation 420 kg of ammonia is reacted with excess hypochlorite to generate 315 kg of hydrazine. What is the percent yield for this unbalanced reaction? NH₃ + OCl^- $\rarr$ N₂H₄ + Cl^- + H₂O

Accepted Answer

The theoretical yield of hydrazine can be calculated from the stoichiometry of the reaction. The percent yield is then calculated as (actual yield/theoretical yield) x 100%. Given the actual yield is 315 kg, the percent yield is 79.7%.

Question 5

Adiponitrile is produced by the reaction of HCN and butadiene:  If 450 kg of butadiene and 400 kg of HCN were to react to completion, what is the maximum amount of adiponitrile that would be produced?

Accepted Answer

The answer of Adiponitrile is produced by the reaction of...

Question 6

Aluminum sulphate is used in finishing paper, among other uses. If 500 kg of aluminum oxide dihydrate react completely with 1500 kg of 90% by mass aqueous H₂SO₄, how many kg of aluminum sulphate can be produced? Al₂O₃ •2H₂O + 3H₂SO₄ $\rarr$ Al₂(SO₄)₃ + 5H₂O

Accepted Answer

The balanced chemical equation is:Al₂O₃ •2H₂O + 3H₂SO₄ $\rarr$ Al₂(SO₄)₃ + 5H₂OFrom the equation, we see that 1 mole of Al₂O₃ •2H₂O reacts with 3 moles of H₂SO₄ to produce 1 mole of Al₂(SO₄)₃.The molar mass of Al₂O₃ •2H₂O is 156 g/mol, and the molar mass of Al₂(SO₄)₃ is 342 g/mol.Therefore, 500 kg of Al₂O₃ •2H₂O is equal to 500 kg / 156 g/mol = 3205 mol.1500 kg of 90% by mass aqueous H₂SO₄ is equal to 1500 kg * 0.9 = 1350 kg of H₂SO₄.1350 kg of H₂SO₄ is equal to 1350 kg / 98 g/mol = 13780 mol.Since 3 moles of H₂SO₄ react with 1 mole of Al₂O₃ •2H₂O, we have 13780 mol / 3 = 4593 mol of H₂SO₄ available to react with Al₂O₃ •2H₂O.Therefore, the limiting reactant is Al₂O₃ •2H₂O, and the maximum amount of Al₂(SO₄)₃ that can be produced is 3205 mol.3205 mol of Al₂(SO₄)₃ is equal to 3205 mol * 342 g/mol = 1.10 x 10⁶ g = 1.10 x 10³ kg.Therefore, the correct answer is A) 1.24 x 10³kg.

Question 7

Thermite is a reaction that was once used to weld railroads together as shown below. A 48.0 g sample of Al(s) was reacted with 99.0 g of Fe₂O₃ according to the equation below. What could be the theoretical yield of Fe_(s) in grams? 2 Al_(s) + Fe₂O_3(s) $\rarr$ Al₂O_3(s)+ 2 Fe_(s)

Accepted Answer

The balanced equation shows that 2 moles of Al react with 1 mole of Fe2O3 to produce 2 moles of Fe. Calculate moles of Al (48.0 g / 26.98 g/mol) and Fe2O3 (99.0 g / 159.69 g/mol). Al is the limiting reactant. Use stoichiometry to find moles of Fe produced and convert to grams (moles of Fe x 55.85 g/mol). The theoretical yield is approximately 69.2 g.

Question 8

Potassium permanganate reacts with hydrochloric acid to give chlorine gas according to unbalanced chemical reaction shown below. If 34.2 g of KMnO₄ were mixed with 0.990 moles of HCl, how many moles of chlorine gas could be produced? KMnO₄ + HCl $\rarr$ MnCl₂ + KCl + Cl_2(g) + H₂O

Accepted Answer

Student must balance reaction.

Question 9

What are the symbols for the following elements?sulphur, fluorine, titanium, potassium, zinc

Accepted Answer

The answer of What are the symbols for the following...

Question 10

What are the names of the elements with the following symbols?
Cr, Na, Cl, Be, He

Accepted Answer

The answer of What are the names of the elements...

Question 11

What are the names of the elements with the following symbols?
Mn, Mg, Md, Rn, Ra

Accepted Answer

The answer of What are the names of the elements...

Question 12

Write formulas of the compounds whose molecular pictures are shown below (unlabelled atoms are carbon).

Accepted Answer

The answer of Write formulas of the compounds whose molecular...

Question 13

Determine the formula of a compound whose molecules each contain two atoms of carbon, two atoms of oxygen and six atoms of hydrogen.

Accepted Answer

The answer of Determine the formula of a compound whose...

Question 14

Name three macroscopic properties of orange juice.

Accepted Answer

The answer of Name three macroscopic properties of orange juice....

Question 15

Plastics are one class of a type of very large molecules called polymers. They are built from smaller building blocks, such as propene. Propene has three carbon atoms and six hydrogen atoms. What is its chemical formula?

Accepted Answer

The answer of Plastics are one class of a type...

Question 16

What are two microscopic properties of a substance?

Accepted Answer

The answer of What are two microscopic properties of a...

Question 17

Use the following information for Questions
3.785 L = 1 gallon; 2.2 lbs = 1 kg; V = EQ \F(4,3) πrS1U1P13S1S1P0S1U1P1;S1S1P0 1 in = 2.54 cm; 1 mile = 1.609 km; 12 in = 1 ft; 1 yard = 3 ft; 1 gal = 3.785 L; ˚C = 5/9 (˚F - 32)
‪ 
-The drive to San Francisco from Los Angeles along the coastal route is 450 miles. What is the distance from Los Angeles to San Francisco expressed in SI units using scientific notation?

Accepted Answer

The answer of Use the following information for Questions
3.785 L...

Question 18

Use the following information for Questions
3.785 L = 1 gallon; 2.2 lbs = 1 kg; V = EQ \F(4,3) πrS1U1P13S1S1P0S1U1P1;S1S1P0 1 in = 2.54 cm; 1 mile = 1.609 km; 12 in = 1 ft; 1 yard = 3 ft; 1 gal = 3.785 L; ˚C = 5/9 (˚F - 32)
‪ 
-What is the volume in SI units of a swimming pool that is 4.5 feet deep by 5 yards wide and 25 yards long?

Accepted Answer

The answer of Use the following information for Questions
3.785 L...

Question 19

Use the following information for Questions
3.785 L = 1 gallon; 2.2 lbs = 1 kg; V = EQ \F(4,3) πrS1U1P13S1S1P0S1U1P1;S1S1P0 1 in = 2.54 cm; 1 mile = 1.609 km; 12 in = 1 ft; 1 yard = 3 ft; 1 gal = 3.785 L; ˚C = 5/9 (˚F - 32)
‪ 
-You fill your car up in Jamaica and it takes 42.3 L of gasoline. How many gallons is this amount?

Accepted Answer

The answer of Use the following information for Questions
3.785 L...

Question 20

Use the following information for Questions 3.785 L = 1 gallon; 2.2 lbs = 1 kg; V = EQ \F(4,3) πrS1U1P13S1S1P0S1U1P1;S1S1P0 1 in = 2.54 cm; 1 mile = 1.609 km; 12 in = 1 ft; 1 yard = 3 ft; 1 gal = 3.785 L; ˚C = 5/9 (˚F - 32) ‪ -Gold has a density of 19.282 g/cm³. What is the mass (in kg) of a sphere of solid gold with a radius of 6.0 cm? (The volume of a sphere is V = EQ \F(4,3) πr³ where r is the radius.)

Accepted Answer

The answer of Use the following information for Questions
3.785 L...

Quiz 1: Fundamental Concepts of Chemistry

How many kg of ethylene oxide is needed to produce 1.05 x 10⁴ kg of ethylene glycol by the following reaction that proceeds in 95% yield?

A way of generating dry O₂ in the lab is to heat potassium chlorate. If you determined that 25 grams of O₂are needed, how much potassium chlorate do you need to start with if there is only a 60% yield?

Adiponitrile is produced by the reaction of HCN and butadiene: If 450 kg of butadiene and 400 kg of HCN were to react to completion, what is the maximum amount of adiponitrile that would be produced?

Aluminum sulphate is used in finishing paper, among other uses. If 500 kg of aluminum oxide dihydrate react completely with 1500 kg of 90% by mass aqueous H₂SO₄, how many kg of aluminum sulphate can be produced? Al₂O₃ •2H₂O + 3H₂SO₄ $\rarr$ Al₂(SO₄) ₃ + 5H₂O

Thermite is a reaction that was once used to weld railroads together as shown below. A 48.0 g sample of Al(s) was reacted with 99.0 g of Fe₂O₃ according to the equation below. What could be the theoretical yield of Fe_(s) in grams? 2 Al_(s) + Fe₂O_3(s) $\rarr$ Al₂O_3(s)+ 2 Fe_(s)

Potassium permanganate reacts with hydrochloric acid to give chlorine gas according to unbalanced chemical reaction shown below. If 34.2 g of KMnO₄ were mixed with 0.990 moles of HCl, how many moles of chlorine gas could be produced? KMnO₄ + HCl $\rarr$ MnCl₂ + KCl + Cl_2(g) + H₂O

What are the symbols for the following elements?sulphur, fluorine, titanium, potassium, zinc

What are the names of the elements with the following symbols? Cr, Na, Cl, Be, He

What are the names of the elements with the following symbols? Mn, Mg, Md, Rn, Ra

Write formulas of the compounds whose molecular pictures are shown below (unlabelled atoms are carbon).

Determine the formula of a compound whose molecules each contain two atoms of carbon, two atoms of oxygen and six atoms of hydrogen.

Name three macroscopic properties of orange juice.

Plastics are one class of a type of very large molecules called polymers. They are built from smaller building blocks, such as propene. Propene has three carbon atoms and six hydrogen atoms. What is its chemical formula?

What are two microscopic properties of a substance?

Quiz 1: Fundamental Concepts of Chemistry

How many kg of ethylene oxide is needed to produce 1.05 x 104 kg of ethylene glycol by the following reaction that proceeds in 95% yield?

A way of generating dry O2 in the lab is to heat potassium chlorate. If you determined that 25 grams of O2 are needed, how much potassium chlorate do you need to start with if there is only a 60% yield?

Hydrazine (N2H4) is made by the reaction of ammonia (NH3) with hypochlorite (OCl-) . Given the following equation 420 kg of ammonia is reacted with excess hypochlorite to generate 315 kg of hydrazine. What is the percent yield for this unbalanced reaction? NH3 + OCl- →\rarr→ N2H4 + Cl- + H2O

Adiponitrile is produced by the reaction of HCN and butadiene: If 450 kg of butadiene and 400 kg of HCN were to react to completion, what is the maximum amount of adiponitrile that would be produced?

Aluminum sulphate is used in finishing paper, among other uses. If 500 kg of aluminum oxide dihydrate react completely with 1500 kg of 90% by mass aqueous H2SO4, how many kg of aluminum sulphate can be produced? Al2O3 •2H2O + 3H2SO4 →\rarr→ Al2(SO4) 3 + 5H2O

Thermite is a reaction that was once used to weld railroads together as shown below. A 48.0 g sample of Al(s) was reacted with 99.0 g of Fe2O3 according to the equation below. What could be the theoretical yield of Fe(s) in grams? 2 Al(s) + Fe2O3(s) →\rarr→ Al2O3(s) + 2 Fe(s)

Potassium permanganate reacts with hydrochloric acid to give chlorine gas according to unbalanced chemical reaction shown below. If 34.2 g of KMnO4 were mixed with 0.990 moles of HCl, how many moles of chlorine gas could be produced? KMnO4 + HCl →\rarr→ MnCl2 + KCl + Cl2(g) + H2O

What are the symbols for the following elements?sulphur, fluorine, titanium, potassium, zinc

What are the names of the elements with the following symbols? Cr, Na, Cl, Be, He

What are the names of the elements with the following symbols? Mn, Mg, Md, Rn, Ra

Write formulas of the compounds whose molecular pictures are shown below (unlabelled atoms are carbon).

Determine the formula of a compound whose molecules each contain two atoms of carbon, two atoms of oxygen and six atoms of hydrogen.

Name three macroscopic properties of orange juice.

Plastics are one class of a type of very large molecules called polymers. They are built from smaller building blocks, such as propene. Propene has three carbon atoms and six hydrogen atoms. What is its chemical formula?

What are two microscopic properties of a substance?

How many kg of ethylene oxide is needed to produce 1.05 x 10⁴ kg of ethylene glycol by the following reaction that proceeds in 95% yield?

A way of generating dry O₂ in the lab is to heat potassium chlorate. If you determined that 25 grams of O₂are needed, how much potassium chlorate do you need to start with if there is only a 60% yield?

Aluminum sulphate is used in finishing paper, among other uses. If 500 kg of aluminum oxide dihydrate react completely with 1500 kg of 90% by mass aqueous H₂SO₄, how many kg of aluminum sulphate can be produced? Al₂O₃ •2H₂O + 3H₂SO₄ $\rarr$ Al₂(SO₄) ₃ + 5H₂O

Thermite is a reaction that was once used to weld railroads together as shown below. A 48.0 g sample of Al(s) was reacted with 99.0 g of Fe₂O₃ according to the equation below. What could be the theoretical yield of Fe_(s) in grams? 2 Al_(s) + Fe₂O_3(s) $\rarr$ Al₂O_3(s)+ 2 Fe_(s)

Potassium permanganate reacts with hydrochloric acid to give chlorine gas according to unbalanced chemical reaction shown below. If 34.2 g of KMnO₄ were mixed with 0.990 moles of HCl, how many moles of chlorine gas could be produced? KMnO₄ + HCl $\rarr$ MnCl₂ + KCl + Cl_2(g) + H₂O